Wet-laid nonwoven sheets of synthetic polymeric fibrids and short length staple fibers are known from U.S. Pat. No. 2,999,788. Increased bonding of these sheets can be obtained by application of heat and/or pressure. As taught in said patent, the fibrids are prepared by shear precipitation of solutions of the polymer, preferably in an aqueous medium. Generally, the fibrids are directly converted into nonwoven sheet structures or paper by paper-forming techniques similar to those employed with wood pulp. Preferably, the aqueous mix used to prepare the nonwoven sheets by paper-making methods will include short fiber or floc in addition to the fibrids. Other materials may be added as desired.
The nature of the floc and fibrids as well as the interaction between them will, of course, determine the sheet properties and the end use applications to which they may be applied. It is an object of the present invention to obtain sheet structures exhibiting high strength and a high glass transition temperature, (Tg). Some of the novel sheet products exhibit outstanding electrical properties as well.